1. Technical Field
The present invention relates to image processing for projectors and, more specifically, to a distortion correction technique for images to be displayed on projection surfaces.
2. Related Art
Projectors generally display images from a low angle onto projection surfaces. With such low-angle image projection, the resulting images displayed on the projection surfaces suffer from distortion. For this reason, in a projector of Patent Document 1 (JP-A-2002-72351), any distorted image is formed in an internally-provided image formation section exemplified by a liquid crystal light valve so that the resulting image to be displayed on the projection surface becomes free from distortion. Note here that the low-angle image projection denotes the projection technique in which the light source optical axis of a projector is not vertical to a projection surface.
With such a previously-known technique, however, there still remains a difficulty in correcting image distortion with accuracy for display on the projection surface.
For distortion correction of images for display on projection surfaces, there originally needs to give consideration to image display areas on the projection surfaces, more specifically, to image display positions and sizes on the projection surfaces. The determination factor for the image display areas is the shift and zoom positions of a projection system, the position and magnification of distorted images to be formed in an image formation section, and the like. However, no consideration has been given to such image display areas, and in Patent Document 1, there is indeed a description of changing the shape of an image formed on a liquid crystal panel depending on the position of a projection lens, but there is no disclosure about the specific technique of making such changes.